When looking in IIS under 'Default Website', have all of the older sites been deleted?

Also, it is not really a supported/recommended configuration to import a 6.9 site into a 7.x instance due to the site redesigns. It will accept the import, however there is a moderate chance you will run into issues down the road.

[2017-10-10T15:44:04.948] [<not set>]: [Error] [ChangeWebSiteAction.InternalValidate]: Parameter: 'ConfigurationName'. Error: Unable to use configuration name 'ARSAdmin' for new configuration because a configuration with this name already exists.

[2017-10-10T15:44:04.949] [<not set>]: [Error] [ArsConfigActionHelper.ProcessError]: Message 'Unable to use configuration name 'ARSAdmin' for new configuration because a configuration with this name already exists.';Parameter name 'ConfigurationName';Stack trace: at ActiveRoles.Web.Configuration.ChangeWebSiteAction.ValidateNotExistingConfiguration(Boolean validateOnly, String configurationName, IWebSiteConfigurationStorage configurationStorage) at ActiveRoles.Web.Configuration.ChangeWebSiteAction.InternalValidate(NewWebSiteParameters parameters, ARWebSite& site, IWebSiteConfigurationStorage& configurationStorage, Boolean isWebAppCreation)

[2017-10-10T15:44:04.949] [<not set>]: [ArsBaseCommand.WriteValidationErrors]: Validation exception: Unable to use configuration name 'ARSAdmin' for new configuration because a configuration with this name already exists.

[2017-10-10T15:44:11.810] [<not set>]: [Error] [ChangeWebSiteAction.InternalValidate]: Parameter: 'ConfigurationName'. Error: Unable to use configuration name 'ARSAdmin' for new configuration because a configuration with this name already exists.

[2017-10-10T15:44:11.811] [<not set>]: [Error] [ArsConfigActionHelper.ProcessError]: Message 'Unable to use configuration name 'ARSAdmin' for new configuration because a configuration with this name already exists.';Parameter name 'ConfigurationName';Stack trace: at ActiveRoles.Web.Configuration.ChangeWebSiteAction.ValidateNotExistingConfiguration(Boolean validateOnly, String configurationName, IWebSiteConfigurationStorage configurationStorage) at ActiveRoles.Web.Configuration.ChangeWebSiteAction.InternalValidate(NewWebSiteParameters parameters, ARWebSite& site, IWebSiteConfigurationStorage& configurationStorage, Boolean isWebAppCreation)

[2017-10-10T15:44:11.811] [<not set>]: [ArsBaseCommand.WriteValidationErrors]: Validation exception: Unable to use configuration name 'ARSAdmin' for new configuration because a configuration with this name already exists.